1. Field of the Invention
The present invention relates to a flying magnetic head and a flying magnetic head assembly for use in such as a magnetic recording/reproducing device which is capable of writing or reading data on or from a magnetic recording medium.
2. Description of the Prior Art
Flying magnetic head assemblies have been known as disclosed in such as U.S. Pat. No. 3,823,416.
FIG. 1 shows a flying magnetic head 1 similar to that disclosed in the above-noted United States Patent. In FIG. 1, the flying magnetic head generally designated by a reference numeral 1 includes a magnetic slider 2 having an air bearing surface on the lower side thereof. A C-shaped core 5 is bonded with an adhesive 4 such as a bonding glass to a trailing surface of the magnetic slider 2 via a nonmagnetic film 3 therebetween. The nonmagnetic film 3 works as a magnetic gap of the flying magnetic head 1. The magnetic slider 2 and the magnetic core 5 are respectively formed of an oxide magnetic material such as a ferrite material. As shown in FIG. 1, an upper surface of the C-shaped core 5 is substantially coplanar with an upper surface of the magnetic slider 2 opposite to the air bearing surface thereof.
FIG. 2 shows a flying magnetic head assembly, wherein known load applying means is attached to the flying magnetic head 1 of FIG. 1. In FIG. 2, a gimbal 7 is fixed at its upper side to a free end portion of a load arm 6 and at its lower side to the upper surface of the magnetic slider 2 opposite to the air bearing surface thereof. Specifically, as shown in FIG. 3 (a) and (b), the gimbal 7 is made of a thin metal plate and includes a tongue 9 which is formed by an elongate slit 8 formed in the thin metal plate. The elongate slit 8 is formed as extending substantially in parallel with sides of the thin metal plate except for one side thereof which is located over the magnetic core 5, so as to provide the tongue 9 and outer side sections 11 and 12 surrounding the tongue 9. On an upper side of the tongue 9 a projection 10 is provided. The load arm 6 is bonded to upper sides of the side sections 11 and 12, and the tongue 9 is bonded at its lower side to the upper surface of the magnetic slider 2 with an adhesive 7a such as a thermosetting epoxy resin. Accordingly, the projection 10 pushes up the load arm 6 along with the side sections 11 and 12 of the gimbal 7 above a level of the tongue 9 as schematically shown in FIG. 2. A pair of grasping claws 13 are formed as extensions of the load arm 6 for holding an insulator tube 14 which receives a conductive wire 15 therethrough. The conductive wire 15 is wound around, the C-shaped core 5 to form a coil.
As shown in FIG. 2, supported by the load arm 6 via the gimbal 7, the magnetic head 1 flies over a magnetic recording disk 16 during a relative movement between the magnetic head 1 and the magnetic recording disk 16 so as to write and read magnetic data on and from the magnetic recording disk 16.
In the prior art structure as described above, however, since the adhesive 7a disposed between the upper surface of the magnetic slider 2 and the tongue 9 of the gimbal 7 is contracted as the setting of the adhesive 7a is advanced, a bending moment M is generated to be applied to the tongue 9 of the gimbal 7 so that the tongue 9 is deformed as shown in FIG. 2. As a result, a portion of the gimbal 7 disposed on the upper surface of the magnetic core 5 but not bonded thereto with the adhesive 7a is also deformed to apply a force F to the upper surface of the magnetic core 5. This inclines the flying magnetic head 1 to displace a bottom surface of the magnetic core 5 by a distance D.sub.1 (about 10 nm ) as indicated by a dotted line in FIG. 2, that is, the bottom surface of the magnetic core 5 exceeds a level of the air bearing surface of the magnetic slider 2 downwardly by the distance D.sub.1. Since the flying magnetic head 1 starts and stops in contact with the magnetic recording disk 16, if the start/stop in-contact operation is repeatedly performed with this inclined posture of the flying magnetic head 1, the magnetic recording disk 16 as well as the magnetic gap of the flying magnetic head 1 are seriously damaged.
In order to overcome this problem, an improved flying magnetic head assembly has been proposed as disclosed in Japanese First (unexamined) Patent Publication No. 3-209615 and as shown in FIGS. 4 and 5.
In FIG. 4, a flying magnetic head 17 includes a magnetic slider 18 and a magnetic core 19 which is bonded with a binding glass 20 to a trailing surface of the magnetic slider 18 with a magnetic gap 25 formed therebetween. An upper surface of the magnetic slider 18 opposite to an air bearing surface thereof is formed into a stepped shape having a level higher surface 18a and a level lower surface 21 which is positioned at a level lower than the level higher surface 18a by a height H. In FIG. 5, load applying means including a load arm 22 and a gimbal 23 is attached to the flying magnetic head of FIG. 4. The load applying means of FIG. 5 is substantially the same as in FIGS. 2 and 3, and the gimbal 23 is bonded to the level higher surface 18a with an adhesive 24.
In the prior art structure of FIGS. 4 and 5, however, there has been raised other serious problems. Specifically, since the cutting or grinding processing of the upper surfaces of the magnetic slider 18 and the magnetic core 19 is required across the magnetic gap 25 for forming the stepped surface having the level higher and lower surfaces 18a and 21, a stress is likely to remain at the magnetic gap 25 to deteriorate the electromagnetic transducing characteristic and further to cause parting at the magnetic gap 25 even with a very small shock. Further, a bonding area between the gimbal 23 and the upper surface of the magnetic slider 18 becomes smaller to cause insufficient bonding strength between the two members 18 and 23. Still further, a bonding area between the magnetic slider 18 and the magnetic core 19 at a portion of the magnetic gap 25 becomes smaller to cause insufficient bonding strength between the two members 18 and 19.